917
FXUS65 KBYZ 201401
AFDBYZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BILLINGS MT
801 AM MDT MON JUL 20 2026
KEY MESSAGES
- COLD FRONT MOVES THROUGH TODAY BRINGING BREEZY NORTHERLY WINDS
AND COOLER CONDITIONS INTO TUESDAY.
- WILDFIRE SMOKE WILL PRODUCE MINOR IMPACTS OVER OUR REGION TODAY
THROUGH TONIGHT.
- CHANCE OF THUNDERSTORMS RETURNS TO MAINLY MOUNTAINS TUESDAY,
THEN MOST OF AREA AT MIDWEEK. HIGH TEMPERATURES WILL BE MAINLY
IN THE 90S.
- POTENTIAL FOR HOTTER CONDITIONS THIS UPCOMING WEEKEND, WITH
WIDESPREAD 100 DEGREE READINGS POSSIBLE.
UPDATE
QUIET WEATHER AND HAZY SKIES ON TAP FOR TODAY. CANADIAN SURFACE
HIGH IS SAGGING SOUTHWARD BUT WON'T QUICK ENOUGH TO PREVENT TEMPS
FROM REACHING THE LOW-MID 90S TODAY, WITH MIXED NORTHERLY SURFACE
WINDS. THESE WINDS WILL TURN EASTERLY TONIGHT AND BRING "COOLER"
TEMPS FOR TUESDAY. IN THE MEANTIME, SKIES WILL REMAIN HAZY PER
NUMEROUS FIRES OVER THE PACNW, THE SMOKE FROM WHICH WILL CONTINUE
TO BE A FACTOR ALOFT EVEN AS SURFACE WINDS PULL IN LESS SMOKY AIR
TONIGHT. WEAK ENERGY ACROSS OUR NORTH WILL BRING A MODEST INCREASE
IN MID/HIGH CLOUDS THROUGH THE DAY, WITH PERHAPS A HINT OF VIRGA
LATE, BUT WITH DRY LOW LEVELS STILL DO NOT SEE A NEED TO MENTION
ACTUAL SHOWERS. FORECAST IS IN GOOD SHAPE. JKL
DISCUSSION
THROUGH SUNDAY...
NORTH/NORTHEAST WINDS WILL ADVECT IN A BAND OF WILDFIRE SMOKE
TODAY. LOOKING AT OBSERVATIONS OF AIR QUALITY TO OUR NORTH,
DANGEROUS AIR QUALITY IS NOT EXPECTED, THOUGH MEMBERS OF SENSITIVE
GROUPS MAY EXPERIENCE HEALTH EFFECTS WITH 24 HOURS OF EXPOSURE.
MODELS CURRENTLY PREDICT THAT THE COLD FRONT WILL PUSH THE
WILDFIRE SMOKE TO OUR SOUTH WITH CLEANER AIR EXPECTED BY TUESDAY
MORNING. EXPECT COOLER TEMPERATURES TODAY IN THE HIGH 80S AND LOW
90S F WITH WINDS GUSTING TO NEAR 30 MPH.
TUESDAY WILL SEE CONTINUED COOLER CONDITIONS WITH HIGH TEMPERATURES
IN THE 80S F. UPPER LEVEL RIDGING BEGINS TO BUILD BACK TUESDAY
ALLOWING MONSOONAL MOISTURE TO RETURN BRINGING 30-40% CHANCES FOR
SHOWERS AND THUNDERSTORMS ALONG THE WYOMING BORDER. WEDNESDAY AND
THURSDAY ARE EXPECTED TO BRING MORE WIDESPREAD 30-60% CHANCES FOR
SHOWERS AND THUNDERSTORMS WITH TEMPERATURES IN THE HIGH 80S TO LOW
90S F. HIGH PWAT VALUES OF 150-225% OF NORMAL WILL CREATE AN
ELEVATED RISK FOR EXTREMELY HEAVY RAINFALL AND ASSOCIATED FLASH
FLOODING RISK THESE DAYS.
UPPER LEVEL RIDGING IS EXPECTED TO CONTINUE FRIDAY THROUGH THE
WEEKEND. THERE ARE SOME MODEL DIFFERENCES IN THE DETAILS HOWEVER.
ENSEMBLE SYSTEMS ARE SHOWING STRONG RIDGING WHILE DETERMINISTIC
MODELS ARE INDICATING A POTENTIAL RIDGE CRASHER. THE RIDGE
CRASHER SCENARIO HAS THE POTENTIAL TO BRING ELEVATED FIRE
CONDITIONS. WHAT IS NOT IN QUESTION IS THAT FRIDAY THROUGH SUNDAY
WILL BE HOT WITH TRIPLE DIGIT HEAT LIKELY (50-90%) FOR THE LOWER
ELEVATIONS. TORGERSON
AVIATION
14Z DISCUSSION...
WILDFIRE SMOKE WILL CREATE SLANT RANGE VISIBILITY REDUCTIONS
ACROSS THE FORECAST AREA. WHILE MVFR VIS IS UNLIKELY AT ANY SITE,
IT CANNOT BE RULED OUT THROUGH 00Z. A STRAY LIGHT SHOWER/SPRINKLE
IS POSSIBLE TODAY ACROSS THE ENTIRE FORECAST REGION (10% CHANCE)
BUT DUE TO LOW CONFIDENCE IT WAS NOT INCLUDED IN ANY TAF. WINDS
WILL SLOWLY SHIFT TO NE THROUGH THE DAY TODAY WITH A WEAK FROPA
PUSHING THROUGH KBIL/KSHR AROUND 02Z WHICH COULD BRING NE WIND
GUSTS UP TO 30 KTS. WMR
PRELIMINARY POINT TEMP/POPS
TDY TUE WED THU FRI SAT SUN
-------------------------------------------------------
BIL 093 066/090 066/091 067/091 067/099 070/100 070/096
0/K 00/E 10/B 22/T 11/U 31/U 21/U
LVM 093 057/088 057/089 057/090 058/096 060/096 059/094
0/K 00/B 24/T 64/T 12/T 21/U 21/U
HDN 095 064/091 064/093 066/091 064/101 067/102 068/098
0/K 00/B 11/B 33/T 00/G 21/G 20/U
MLS 093 063/086 064/093 067/092 067/102 072/104 072/100
0/K 00/B 00/B 22/T 00/G 21/G 21/U
4BQ 094 064/088 065/092 066/088 065/097 070/101 071/098
0/K 00/B 31/B 45/T 10/U 11/G 11/U
BHK 092 057/084 059/090 061/091 062/099 068/104 068/100
0/N 00/B 00/B 11/B 10/U 11/G 11/U
SHR 093 059/091 061/090 061/086 059/096 063/098 064/095
0/K 10/K 44/T 68/T 21/U 01/U 11/U
BYZ WATCHES/WARNINGS/ADVISORIES
MT...NONE.
WY...NONE.
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